1. Industrial Field of the Invention
The present invention relates to a fuel pump and, more particularly, to a regenerative type fuel pump for pressurizing and pumping fuel.
2. Description of the Prior Art
Conventionally, a regenerative type pump for pressurizing and pumping fuel is known as a fuel supply device of an internal combustion engine for an automobile.
In a regenerative fuel pump disclosed in, for example, Japanese Patent Unexamined Publication No. 58-210394, a fuel suction port is formed to be enlarged toward a rotary shaft of an impeller, to prevent flow rate reduction of fuel at a high temperature.
In a fuel pump disclosed in Japanese Utility Model Unexamined Publication No. 64-25494, a groove for a pump channel is the deepest at its inlet portion and the depth of the groove gradually becomes smaller, so as to restrict the occurrence of fuel vapor.
The conventional fuel pump having the above structure, has tried to prevent the decrease of the fuel flow rate at the high temperature by improving the shape of the suction port of the regenerative fuel pump. However, with the shape of the suction port in the pump disclosed in Japanese Patent Unexamined Publication No. 58-210394, a measure of enlarging the inlet portion is chosen, but a satisfactory characteristic of the flow rate cannot still be obtained.
Also, with the shape as disclosed in Japanese Utility Model Unexamined Publication No. 64-25494, the inlet portion is not large enough to prevent the occurrence of the fuel vapor at the inlet portion sufficiently. Thus, the satisfactory characteristic of the flow rate cannot still be obtained.
In view of the above-described disadvantages of the prior art, the present invention aims to provide a fuel pump which can restrain flow rate reduction of fuel at a high temperature and obtain a sufficient flow rate of fuel even at the high temperature, by improving the structure of the portion extending between the suction port and the inlet portion of the regenerative fuel pump.